High performance stage assembly

ABSTRACT

A stage assembly ( 10 ) for moving and positioning one or more objects ( 24 ) for an exposure apparatus ( 28 ) is provided herein. The stage assembly ( 10 ) includes a fine stage ( 14 ) and a coarse stage ( 18 ). The fine stage ( 14 ) includes a holder ( 15 ) that retains the object ( 24 ). The stage assembly ( 10 ) also includes a fine Y mover ( 32 ) and a fine X mover ( 34 ) that precisely move the fine stage ( 14 ) relative to the coarse stage ( 18 ). Uniquely, the fine movers ( 32 ), ( 34 ) are positioned on only one side of the holder ( 15 ). With this design, the resulting stage assembly ( 10 ) has a relatively low mass and a relatively high servo bandwidth. Further, with this design, the stage assembly ( 10 ) is readily accessible for service and a measurement system ( 16 ) can be easily positioned near the fine stage ( 14 ). The stage assembly ( 10 ) can also include an anti-gravity mechanism ( 40 ) that minimizes distortion of a stage base ( 12 ) that supports the fine stage ( 14 ) as the fine stage ( 14 ) moves above the stage base ( 12 ). Additionally, the stage assembly ( 10 ) can include a reaction assembly ( 20 ) that reduces the amount of reaction forces transferred from the coarse stage ( 18 ).

RELATED APPLICATION

[0001] This application is a continuation of application Ser. No.09/471,740 filed on Dec. 23, 1999, entitled “HIGH PERFORMANCE STAGEASSEMBLY” which is currently pending. The contents of application Ser.No. 09/471,740 is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention is directed to a stage for an exposureapparatus. More specifically, the present invention is directed to a lowmass, high performance stage for an exposure apparatus.

BACKGROUND

[0003] Exposure apparatuses are commonly used to transfer images from areticle onto a semiconductor wafer during semiconductor processing. Atypical exposure apparatus includes an illumination source, a reticlestage retaining a reticle, a lens assembly and a wafer stage retaining asemiconductor wafer. The reticle stage and the wafer stage are supportedabove a ground with an apparatus frame. Typically, one or more motorsprecisely position the wafer stage and one or more motors preciselyposition the reticle stage. The images transferred onto the wafer fromthe reticle are extremely small. Accordingly, the precise relativepositioning of the wafer and the reticle is critical to themanufacturing of high density, semiconductor wafers.

[0004] A typical reticle stage includes a coarse stage and a fine stage.The coarse stage is used for relatively large movements of the reticleand the fine stage is used for relatively small, precise movements ofthe reticle. Existing reticle stages typically utilize a pair of spacedapart fine Y motors to move the fine stage along a Y axis and a pair ofspaced apart coarse Y motors to move the coarse stage along the Y axis.

[0005] Unfortunately, existing reticle stages that utilize both a coarsestage and a fine stage have a relatively large total mass. As a resultof the large mass, large motors are needed to move and position the finestage and the coarse stage. These motors occupy valuable space near thestage, consume large amounts of electric current and generate asignificant amount of heat. The heat is subsequently transferred to thesurrounding environment, including the air surrounding the motors andthe other components positioned near the motors. The heat changes theindex of refraction of the surrounding air. This reduces the accuracy ofany metrology system used to monitor the positions of the stages anddegrades machine positioning accuracy. Additionally, the heat causesexpansion of the other components of the device. This further degradesthe accuracy of the device.

[0006] Moreover, a large mass, reticle stage has a relatively lowresonant frequency and a low servo bandwidth. As a result of the lowresonant frequency and low servo bandwidth, external forces and/or smallreaction forces can easily vibrate and distort the reticle stage. Thiswill influence the position of the reticle stage and the performance ofthe exposure apparatus.

[0007] Additionally, the multiple motors required for both the coarsestage and the fine stage complicates the layout of the reticle stage andthe system required to control both the coarse stage and the fine stage.

[0008] In light of the above, it is an object of the present inventionto provide a stage assembly that has a relatively low mass, a relativelyhigh resonance frequency and a relatively high servo bandwidth. Anotherobject is to provide a stage assembly that is relatively simple tocontrol, allows space for service access, and allows space for ameasurement system. Still another object is to provide a stage assemblythat utilizes efficient motors to move the components of the stageassembly. Yet another object is to provide a low mass stage assemblythat can simultaneously carry two reticles. Another object is to providea stage assembly that offsets the mass of a fine stage to minimizedistortion to a stage base and a lens assembly. Another object is toprovide a stage that utilizes reaction force cancellation to minimizethe forces transferred to a mounting frame. Still another object is toprovide an exposure apparatus capable of manufacturing high density,semiconductor wafers. Yet another object is to provide a stage assemblyhaving a guideless fine stage and a guideless coarse stage.

SUMMARY

[0009] The present invention is directed to a stage assembly for movingan object that satisfies these needs. The stage assembly includes a finestage and a coarse stage. The fine stage includes a holder that retainsthe object. As provided herein, the stage assembly can be used toprecisely position one or more objects during a manufacturing and/or aninspection process.

[0010] The stage assembly includes a fine Y mover and a fine X moverthat precisely move the fine stage relative to the coarse stage.Additionally, the stage assembly can also include a coarse Y mover and acoarse X mover that move the coarse stage relative to a reactionassembly. Uniquely, the fine movers and the coarse movers are positionedon only one side of the holder. With this design, the fine stage has arelatively low mass and a relatively high servo bandwidth. Because ofthe low mass, smaller movers can be used to move the fine stage. Becauseof the high servo bandwidth, external forces and small reaction forcesare less likely to influence the position of the fine stage. This allowsfor more accurate positioning of the object by the stages and theproduction of higher quality wafers. Further, with this design, thestage assembly is easily accessible for service and the measurementsystem can be easily positioned near the fine stage.

[0011] Moreover, both the fine stage and the coarse stage are guidelessalong the X axis, along the Y axis and about the Z axis. Morespecifically, both the fine stage and the coarse stage are notconstrained along the Y axis, the X axis and about the Z axis. Statedanother way, each stage can be moved with at least three degrees offreedom. With this design, the movers control the position of the stagesalong the X axis, along the Y axis and about the Z axis. This allows formore accurate positioning of the stages and better performance of thestage assembly.

[0012] Further, the stage assembly can also include an anti-gravitymechanism that urges the fine stage upwards towards the coarse stage.This minimizes distortion to a stage base that supports the fine stageas the fine stage moves above the stage base.

[0013] Additionally, the stage assembly can include a mounting framethat supports the reaction assembly and allows the reaction assembly tomove relative to the mounting frame. With this design, the reactionassembly reduces the amount of reaction forces from the coarse moversthat are transferred to the ground.

[0014] The present invention is also directed to a method for moving anobject, a method for manufacturing a stage assembly, a method formanufacturing an exposure apparatus and a method for manufacturing awafer and a device.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The novel features of this invention, as well as the inventionitself, both as to its structure and its operation, will be bestunderstood from the accompanying drawings, taken in conjunction with theaccompanying description, in which similar reference characters refer tosimilar parts, and in which:

[0016]FIG. 1 is an upper perspective view of a stage assembly havingfeatures of the present invention;

[0017]FIG. 2 is front plan view of the stage assembly of FIG. 1, with astage base and a measurement system omitted for clarity;

[0018]FIG. 3 is a side plan view of the stage assembly of FIG. 1, withthe stage base and the measurement system omitted for clarity;

[0019]FIG. 4 is an exploded perspective view of the stage assembly ofFIG. 1, without the stage base and the measurement system;

[0020]FIG. 5 is a top, partly exploded, perspective view of a fine stagehaving features of the present invention;

[0021]FIG. 6 is a bottom perspective view of the fine stage of FIG. 5;

[0022]FIG. 7 is a perspective view of a mover having features of thepresent invention;

[0023]FIG. 8 is an exploded perspective view of the mover of FIG. 7;

[0024]FIG. 9 is a cross-sectional view taken on line 9-9 of FIG. 3;

[0025]FIG. 10 is a perspective view of the view of FIG. 9;

[0026]FIG. 11 is a side perspective view, in partial cut-away of thestage assembly of FIG. 1;

[0027]FIG. 12 is another side perspective view of the stage assembly ofFIG. 1;

[0028]FIG. 13 is an illustration of an exposure apparatus havingfeatures of the present invention;

[0029]FIG. 14 is a flow chart that outlines a process for manufacturinga device in accordance with the present invention; and

[0030]FIG. 15 is a flow chart that outlines device processing in moredetail.

DESCRIPTION

[0031] Referring initially to FIGS. 1-4, a stage assembly 10 havingfeatures of the present invention includes a stage base 12, a fine stage14 including a holder 15, a measurement system 16, a coarse stage 18, areaction assembly 20 and a mounting frame 22. The stage assembly 10 isuseful for precisely positioning one or more objects 24 during amanufacturing and/or inspection process.

[0032] The type of object 24 positioned and moved by the stage assembly10 can be varied. In the embodiments provided herein, each object 24 isa reticle 26 and the stage assembly 10 is useful as part of an exposureapparatus 28 (illustrated in FIG. 13) for precisely positioning eachreticle 26 during the manufacture of a semiconductor wafer 30(illustrated in FIG. 13). Alternately, for example, the stage assembly10 can be used to retain a reticle during reticle manufacturing, anobject under an electron microscope (not shown), an object during aprecision measurement operation, or an object during a precisionmanufacturing operation.

[0033] As an overview, the stage assembly 10 also includes a fine Ymover 32, a fine X mover 34, a coarse Y mover 36, a coarse X mover 38and an anti-gravity mechanism 40. The fine Y mover 32 and the fine Xmover 34 precisely move the fine stage 14 relative to the coarse stage18. The coarse Y mover 36 (illustrated in FIGS. 9 and 10) and the coarseX mover 38 move the coarse stage 18 relative to the reaction assembly20. The anti-gravity mechanism 40 minimizes distortion of the stage base12 as the fine stage 14 moves above the stage base 12.

[0034] The fine stage movers 32, 34 and the coarse stage movers 36, 38are uniquely positioned on only one side of the holder 15. With thisdesign, the fine stage 14 has a relatively low mass and a relativelyhigh servo bandwidth. Because of the low mass, smaller movers 32, 34 canbe used to move the fine stage 14. The smaller movers 32, 34 generateless heat and consume less energy. Because of the high servo bandwidth,external forces and small reaction forces are less likely to influencethe position of the fine stage 14. This allows for more accuratepositioning of the object 24 by the stages 14,18 and the production ofhigher quality wafers 30. Further, with this design, the stage assembly10 is readily accessible for service and the measurement system 16 canbe easily positioned near the fine stage 14.

[0035] Some of the Figures provided herein include a coordinate systemthat designates an X axis, a Y axis and a Z axis. It should beunderstood that the coordinate system is merely for reference and can bevaried. For example, the X axis can be switched with the Y axis.

[0036] Importantly, as provided herein, both the fine stage 14 and thecoarse stage 18 are guideless along the X axis, along the Y axis andabout the Z axis. More specifically, both the fine stage 14 and thecoarse stage 18 are not constrained along the Y axis, the X axis andabout the Z axis. Stated another way, each stage 14,18 can be moved withat least three degrees of freedom. With this design, the fine movers 32,34 precisely control the position of the fine stage 14 along the X axis,along the Y axis and about the Z axis and the coarse movers 36, 38control the position of the coarse stage 18 along the X axis, along theY axis and about the Z axis. This allows for more accurate control overthe positions of the stages 12, 14 and better performance of the stageassembly 10.

[0037] The stage base 12 supports the fine stage 14 during movement. Thedesign of the stage base 12 can be varied to suit the designrequirements of the stage assembly 10. In the embodiment illustrated inFIG. 1, the stage base 12 is a generally rectangular shaped plate. Thestage base 12 includes a planar upper base surface 42 and an opposed,lower base surface 44. The stage base 12 also includes a base aperture46 and a lens cut-out 48. The base aperture 46 extends through the stagebase 12 and allows for the passage of light through the stage base 12.The lens cut-out 48 is somewhat cylindrical shaped and extends partlyinto the stage base 12 from the lower base surface 44. The lens cut-out48 allows for the positioning of a lens assembly 50 (illustrated in FIG.13) near the first stage 14.

[0038] The fine stage 14 precisely positions the one or more objects 24.The design of fine stage 14 and the degrees of freedom of the fine stage14 relative to the stage base 12 can be varied. In the embodimentillustrated in the figures, the fine stage 14 is guideless and moved bythe fine movers 32, 34 with a limited range of motion along the X axis,the Y axis and about the Z axis (theta Z) relative to the coarse stage18. Referring to FIGS. 4-6, the fine stage 14 includes a fine frame 52,a first portion 54 of the fine Y mover 32, a first portion 56 of thefine X mover 34, a first portion 58 of the anti-gravity mechanism 40 anda first potion 60 of the measurement system 16.

[0039] The combination of the fine stage 14 and the one or more objects24 have a combined center of gravity 61 (illustrated as a dot in FIGS. 9and 10). Importantly, the fine Y mover 32 engages the fine stage 14 nearthe combined center of gravity 61. This minimizes the coupling ofacceleration of the fine Y mover 32 to movement along the X axis andabout the Z axis of the fine stage 14. Stated another way, thisminimizes the forces on the fine stage 14 along the X axis and about theZ axis, generated by the fine Y mover 32. With this design, the fine Ymover 32 does not tend to move the fine stage 14 along the X axis orrotate the fine stage 14 about the Z axis. As a result of this design,the force required to move the fine stage 14 along the X axis and aboutthe Z axis is minimized. This allows for the use of a smaller andlighter, fine X mover 34.

[0040] The fine frame 52 is generally rectangular shaped and includes afine frame bottom 62, a fine frame top 64, a first fine frame side 66, asecond fine frame side 68 substantially opposite the first fine frameside 66, a front fine frame side 70 and a rear fine frame side 72substantially opposite the front fine frame side 70. The fine frame 52is preferably made of a ceramic material having a low rate of thermalexpansion.

[0041] The fine frame bottom 62 includes a plurality of spaced apartfluid outlets (not shown) and a plurality of spaced apart fluid inlets(not shown). Pressurized fluid (not shown) is released from the fluidoutlets towards the stage base 12 and a vacuum is pulled in the fluidinlets to create a vacuum preload type, fluid bearing between the fineframe 52 and the stage base 12. The vacuum preload type, fluid bearingmaintains the fine stage 14 spaced apart along the Z axis relative tothe stage base 12 and allows for motion of the fine stage 14 along the Xaxis, the Y axis and about the Z axis relative to the stage base 12. Thevacuum preload fluid bearing maintains a high stiffness connectionbetween the fine stage 14 and the stage base 12 along the Z axis, aboutthe X axis and about the Y axis, despite the approximately zero netgravity force of the fine stage 14 as a result of the anti-gravitymechanism 40. Alternately, the fine stage 14 can be supported above thestage base 12 by alternate ways such as magnetic type bearing (notshown).

[0042] The fine frame 52 also includes one or more holders 15, amid-wall 74 and a stiffener 76. Each holder 15 retains and secures oneof the objects 24, e.g. reticles 26, to the fine stage 14. In theembodiment illustrated in the figures, each holder 15 is a rectangularshaped cut-out with vacuum chucks on either side. Each holder 15includes a first holder side 78, an opposed second holder side 80, afront holder side 82 and a rear holder side 84. The number of holders 15can be varied. For example, in the embodiment illustrated in theFigures, the fine stage 14 includes two spaced apart holders 15. Becauseof the unique design provided herein, a relatively low mass stageassembly 10 that retains two reticles 26 can be manufactured.Alternately, the fine stage 14 could include a single holder 15 forretaining only one reticle 26.

[0043] Importantly, as provided below, the required stroke of the coarsestage 18 along the Y axis will vary according to the number of objects24 retained by the fine stage 14. More specifically, the stroke of thecoarse stage 18 along the Y axis will need to be increased as the numberof objects 24 is increased.

[0044] The mid-wall 74 extends upwardly from the fine frame top 64 andsecures the first portion 54 of the fine Y mover 32 and the firstportion 58 of the anti-gravity mechanism 40 to the fine frame 52. In theembodiment illustrated n the Figures, the mid-wall 74 is a flat, planarwall. The mid-wall 74 includes a plurality of spaced apart wallapertures 86 that extend transversely through the mid-wall 74. Asillustrated in FIG. 5, the mid-wall 74 also includes a plurality ofpairs of spaced apart pins 88 and a plurality of spaced apart internallythreaded apertures 90 for securing the first portion 54 of the fine Ymover 32 and the first portion 58 of the anti-gravity mechanism 40 tothe mid-wall 74.

[0045] The mid-wall 74 extends along the Y axis between the first fineframe side 66 and the first holder side 78. The mid-wall 74 ispreferably extends near the combined center of gravity 61 so that thefine Y mover 32 is maintained near the combined center of gravity 61. Inthe embodiments provided herein, the combined center of gravity 61 isnear the mid-wall 74 approximately half way between the front fine frameside 70 and the rear fine frame side 72. With this design, the forcefrom the fine Y mover 32 is directed through the combined center ofgravity 61.

[0046] The stiffener 76 provides stiffness to the fine stage 14 andinhibits bending and flexing of the fine stage 14. Additionally, thestiffener 76 adds mass to the fine stage 14 so that the combined centerof gravity 61 is near the mid-wall 74. The design and location of thestiffener 76 can be varied to suit the design of the fine stage 14. Inthe embodiment illustrated in the Figures, the stiffener 76 isrectangular “U” shaped and extends along the first fine frame side 66.The first portion 56 of the fine X mover 34 is secured to the stiffener76 near the front fine frame side 70 and the rear fine frame side 72.

[0047] Preferably, the fine stage 14 includes one or more stage openings92 that are strategically positioned to lighten the mass of the finestage 14 and balance the mass of the fine stage 14, without compromisingthe structural strength of the fine stage 14. The number and design ofthe stage openings 92 can be varied. In the embodiment illustrated inthe Figures, the fine stage 14 includes four, rectangular shaped stageopenings 92 that extend partly into the fine frame top 64. The stageopenings 92 are located between the mid-wall 74 and the first fine frameside 66 of the fine frame 52.

[0048] As provided above, the fine movers 32, 34 move the fine stage 14with a limited range of motion along the X axis, the Y axis and aboutthe Z axis relative to the coarse stage 18. More specifically, the fineY mover 32 moves the fine stage 14 relative to the coarse stage 18 alongthe Y axis and the fine X mover 34 moves the fine stage 14 relative tothe coarse stage 18 along the X axis and around the theta Z axis.

[0049] The design of each fine movers 32, 34 can be varied to suit thedesign requirements of the stage assembly 10. In the embodimentillustrated in the Figures, each fine Y mover 32 includes the firstportion 54 that is secured to the fine stage 14 and a second portion 94that is secured to the coarse stage 18. The first portion 54 and thesecond portion 94 of the fine Y mover 32 interact to selectively movethe fine stage 14 along the Y axis.

[0050] Somewhat similarly, each fine X mover 34 includes the firstportion 56 that is secured to the fine stage 14 and a second portion 96that is secured to the coarse stage 18. The first portion 56 and thesecond portion 96 of the fine X mover 34 interact to selectively movethe fine stage 14 along the X axis and about the Z axis.

[0051] In the embodiment illustrated in the Figures, the fine Y mover 32and the fine X mover 34 each include a plurality of spaced apart pairsof opposed, attraction only actuators 98. More specifically, the fine Ymover 32 includes five, spaced apart pairs of opposed, attraction onlyactuators 98 and the fine X mover 34 includes two, spaced apart pairs ofopposed, attraction only actuators 98.

[0052] The attraction only type actuators 98 consume less power andgenerate less heat than a voice coil motor or a linear motor. Thisminimizes the need to cool the fine movers 32, 34. Further, because thefine movers 32, 34 are each located on only on side of the holder 15,any heat from the fine movers 32, 34 can be easily directed away fromthe measurement system 16.

[0053]FIGS. 7 and 8 illustrate a perspective view of a preferredattraction only actuator 98. More specifically, FIG. 7 illustrates aperspective view of a type of attraction only actuator 98 commonlyreferred to as an E/I core actuator and FIG. 8 illustrates an explodedperspective view of the E/I core actuator. Each E/I core actuator isessentially an electo-magnetic attractive device. Each E/I core actuatorincludes an E shaped core 100, a tubular coil 102, and an I shaped core104. The E core 100 and the I core 104 are each made of a magneticmaterial such as iron. The coil 102 is positioned around the center barof the E core 100. Current (not shown) directed through the coil 102creates an electromagnetic field that attracts the I core 104 towardsthe E core 100. The amount of current determines the amount ofattraction.

[0054] In the embodiments provided herein, (i) the I core 104 of eachattraction only actuator 98 is considered the first portion 54, 56 ofeach fine mover 32, 34 and is secured to the fine stage 14, and (ii) theE core 100 and coil 102 of each attraction only actuator 98 isconsidered the second portion 94, 96 of each fine mover 32, 34 and issecured to the coarse stage 18.

[0055] Specifically, the fine Y mover 32 includes five pairs of spacedapart, I cores 104 (ten total I cores) secured to the mid-wall 74 andfive pairs of spaced apart, E cores 100 and coils 102 (ten total E coresand ten coils 102) secured to the coarse stage 18. The fine Y mover 32is preferably centered on the combined center of gravity 61.

[0056] Somewhat similarly, the fine X mover 34 includes two sets of twospaced apart, I cores 104 (four total I cores) and two sets of twospaced apart, E cores 100 and coils 102 (four total E cores 100 andcoils 102). One of the sets of I cores 104 is secured to each end of thestiffener 76 and the two sets of E cores 100 and coils 102 are securedto the coarse stage 18.

[0057] This arrangement is preferred because no electrical wiresassociated with the fine movers 32, 34 are directly connected to thefine stage 14. This reduces interference to the fine stage 14.Alternately, the mounting of the attraction only actuators 98 could bereversed. In this proposed configuration, the I cores 104 would beattached to the coarse stage 18 while the E cores 100 and coils 102would be secured to the fine stage 14.

[0058] The anti-gravity mechanism 40 offsets the weight of the finestage 14 and minimizes distortion of the stage base 12 as the fine stage14 moves relative to the stage base 14. More specifically, theanti-gravity mechanism 40 pulls upward on the fine stage 14 as the finestage 14 moves relative to the stage base 12 to inhibit the location ofthe fine stage 14 from influencing the stage base 12.

[0059] In the embodiment illustrated in the Figures, the anti-gravitymechanism 40 includes a pair of spaced apart attraction only actuators106. Each attraction only actuator 106 includes the first portion 58that is secured to the top of the mid-wall 74 and a second portion 108that is secured to the coarse stage 18.

[0060] Preferably, each attraction only actuator 106 is an E/I coreactuator as described above. With this design, two spaced apart I cores104 are secured to the top of the mid-wall 74 and two spaced apart Ecores 100 and coils 102 are secured to the coarse stage 18. Alternately,the mounting of the I core 104 and the E core 100 can be reversed.

[0061] Importantly, the anti-gravity mechanism 40 is also positionednear the combined center of gravity 61 and the fine Y mover 32 so thatthe anti-gravity mechanism 40 can lift the fine stage 14 along the Zaxis to counteract the influence of fine stage 14 on the stage base 12.Further, the amount of attraction generated by the anti-gravitymechanism 40 can be adjusted by adjusting the current to the coil 102.

[0062] The measurement system 16 monitors the position of the fine stage14 relative to the stage base 12. With this information, the position ofthe fine stage 14 can be adjusted. The design of the measurement system16 can be varied. In the embodiment illustrated in FIG. 1, themeasurement system 16 includes the first portion 60 that is part of andmounted to the fine stage 14 and a second portion 110.

[0063] Referring to FIG. 1, the first portion 60 of the measurementsystem 16 includes a X interferometer mirror 112 and a pair of spacedapart Y interferometer mirrors 114 while the second portion 110 includesa X interferometer block 116 and a Y interferometer block 118.Alternately, these components can be reversed.

[0064] The X interferometer block 116 interacts with the Xinterferometer mirror 112 to monitor the location of the fine stage 14along the X axis. More specifically, the X interferometer block 116generates a measurement signal (not shown) that is reflected off of theX interferometer mirror 112. With this information, the location of thefine stage 14 along the X axis can be monitored. In the embodimentillustrated in the Figures, the X interferometer mirror 112 isrectangular shaped and extends along the second fine frame side 68 ofthe fine frame 52. The X interferometer block 116 is positioned awayfrom the fine stage 14. The X interferometer block 116 can be secured toan apparatus frame 120 (illustrated in FIG. 13) or some other locationthat is isolated by vibration.

[0065] The Y interferometer mirrors 114 interact with the Yinterferometer block 118 to monitor the position of the fine stage 14along the Y axis and about the Z axis (theta Z). More specifically, theY interferometer block 118 generates a pair of spaced apart measurementsignals (not shown) that are reflected off of the Y interferometermirrors 114. With this information, the location of the fine stage 14along the Y axis and about the Z axis can be monitored. In theembodiment illustrated in the Figures, each Y interferometer mirror 114is somewhat “V” shaped and is positioned along the rear fine frame side72 of the fine frame 52. The Y interferometer block 118 is positionedaway from the fine stage 14. The Y interferometer block 118 can besecured to an apparatus frame 120 or some other location that isisolated from vibration.

[0066] Importantly, because the fine movers 32, 34 and the coarse movers36, 38 are positioned on only one side of the holder 15, the measurementsystem 16 can be easily positioned near the fine stage 14.

[0067] The coarse stage 18 keeps the second portion of the fine Y mover94 and the second portion of the fine X mover 96 near the fine stage 14over the long stroke. This allows for the use of relatively shorttravel, efficient fine Y mover 32 and fine X mover 34.

[0068] The design of coarse stage 18 and the degrees of freedom of thecoarse stage 18 relative to the reaction assembly 20 can be varied. Inthe embodiment illustrated in the figures, the coarse stage 18 isguideless in the planar degrees of freedom and is moved by the coarsemovers 36, 38 a relatively long displacement along the Y axis and arelatively short displacement along the X axis and around the Z axis(theta Z). More specifically, the coarse stage 18 illustrated in theFigures is moved by the coarse Y mover 36 relative to the reactionassembly 20 a relatively long displacement along the Y axis. Further,the coarse stage 18 is moved by the coarse X mover 38 a relatively shortdisplacement along the X axis and around the Z axis (theta Z).

[0069] Further, in the embodiments illustrated in the Figures, thecoarse stage 18 is positioned above the fine stage 14.

[0070] Referring to FIGS. 4, and 9-12, the coarse stage 18 includes acoarse frame 122, the second portion 94 of the fine Y mover 32, thesecond portion 96 of the fine X mover 34, the second portion 108 of theanti-gravity mechanism 40, a first portion 124 of the coarse Y mover 36,and a first portion 126 of the coarse X mover 38.

[0071] The combination of the fine stage 14, the objects 24 and thecoarse stage 18 have a combination center of gravity 128 (illustrated asa dot in FIGS. 9 and 10). Importantly, the coarse Y mover 36 engages thecoarse stage 18 near the combination center of gravity 128. Thisminimizes the coupling of acceleration of the coarse Y mover 36 tomovement along the X axis and about the Z axis of the coarse stage 18.Stated another way, this minimizes the forces on the coarse stage 18along the X axis and about the Z axis, generated by the coarse Y mover36. With this design, the coarse Y mover 36 does not tend to move thecoarse stage 18 along the X axis or rotate the coarse stage 18 about theZ axis. As a result of this design, the force required to move thecoarse stage 18 along the X axis and about the Z axis is minimized. Thisallows for the use of a smaller, lighter mass, coarse X mover 38.

[0072] The coarse frame 122 illustrated in the Figures is generallyrectangular tube shaped and includes a coarse frame bottom 130, a coarseframe top 132, a first coarse frame side 134 and a second coarse frameside 136 substantially opposite the first coarse frame side 134. Thecoarse frame 122 can be made of a number of materials, including aceramic material or aluminum.

[0073] The coarse frame bottom 130 supports the second portion 96 of thefine X mover 34 and the first portion 124 of the coarse Y mover 36. Morespecifically, a pair of attachment plates 138 cantilever downward fromcoarse frame bottom 130 intermediate the coarse frame sides 134, 136.One of the attachment plates 138 is positioned on the front of thecoarse stage 18 while the other attachment plate 138 is positioned onthe rear of the coarse stage 18. The second portion 96 of the fine Xmover 34 (e.g., a pair of E cores 100 and a pair of coils 102) isattached to each attachment plate 138.

[0074] The first portion 124 of the coarse Y mover 36 is secured to thecoarse frame bottom 130 and extends along the length of the coarse stagebottom 130 between the front and rear of the coarse stage 18. In theembodiment illustrated in the Figures, a rectangular shaped, attachmentbar 140 is positioned between and used to secure the first portion 124of the coarse Y mover 36 to the coarse frame bottom 130. The attachmentbar 140 is secured to the first portion 124 of the coarse Y mover 36 andthe coarse frame bottom 130 with an attachment bolt (not shown).

[0075] In the embodiment provided herein, the combination center ofgravity 128 is near the center of the first portion 124 of the coarse Ymover 36 approximately half way between the front and the rear of thecoarse stage 18.

[0076] In the embodiments provided herein, the coarse frame top 132 issupported between a pair of spaced apart bearing plates 142 of thereaction assembly 20. The coarse frame top 132 is generally planarshaped and includes an upper surface 144 and a lower surface 146. Theupper surface 144 and the lower surface 146 of the coarse frame top 132each include a plurality of spaced apart fluid outlets (not shown).Pressurized fluid (not shown) is released from the fluid outlets towardsthe bearing plates 142 of the reaction assembly 20 to create a fluidbearing between the coarse frame top 132 and the bearing plates 142. Thefluid bearing maintains the coarse frame top 132 spaced between thebearing plates 142 and allows for relatively large movement of thecoarse stage 18 relative to the reaction assembly 20 along the Y axis,and smaller movement along the X axis and about the Z axis relative tothe reaction assembly 20. Alternately, the coarse stage 18 can besupported by the reaction assembly 20 by other ways such as magnetictype bearing (not shown). In another alternate embodiment, the coarsestage 18 can be supported by the reaction assembly 20 having only onebearing plate with a vacuum preload type fluid bearing (not shown).

[0077] The first coarse frame side 134 extends between coarse framebottom 130 and the coarse frame top 132 and secures the first portion126 of the coarse X mover 34 to the coarse stage 18. In the embodimentillustrated in the Figures, the first portion 126 is positionedintermediate the coarse frame bottom 130 and the coarse frame top 132.

[0078] The second coarse frame side 136 extends between coarse framebottom 130 and the coarse frame top 132 and secures the second portion94 of the fine Y mover 32 and the second portion 108 of the anti-gravitymechanism 40 to the coarse stage 18. More specifically, a sideattachment plate 148 cantilevers downward from the second coarse frameside 136 and a pair of spaced apart, three beam assemblies 150 extendtransversely from the second coarse frame side 136. The second portion94 of the fine Y mover 32 (e.g., ten spaced apart E cores 100 and tencoils 102) is secured to the side attachment plate 148. The secondportion 108 of the anti-gravity mechanism 40 (e.g., two spaced apart Ecores 100 and two coils 102) is retained by the three beam assemblies150 to the second coarse frame side 136.

[0079] The design of each coarse movers 36, 38 can be varied to suit thedesign requirements of the stage assembly 10. In the embodimentillustrated in the Figures, each coarse Y mover 36 includes the firstportion 124 that is secured to the coarse stage 18 and a second portion152 that is secured to the reaction assembly 20. The first portion 124and the second portion 152 of the coarse Y mover 36 interact toselectively move the coarse stage 18 along the Y axis. Somewhatsimilarly, each coarse X mover 38 includes two of the first portion 126that is secured to the coarse stage 18 and a second portion 154 that issecured to the reaction assembly 20. The first portions 126 and thesecond portion 154 of the coarse X mover 38 interact to selectively movethe coarse stage 18 along the X axis and about the Z axis.

[0080] In the embodiment illustrated in the Figures, the coarse Y mover36 is a linear motor. In this embodiment, the first portion 124 of thecoarse Y mover 36 includes a plurality of spaced apart coils (not shown)aligned in a coil array (not shown) while the second portion 152 of thecoarse Y mover 36 includes a pair of spaced apart Y magnet arrays 156.Each Y magnet array 156 is positioned on one of the sides of the coilarray. The coil array extends the length of the coarse frame 122 and isdisposed within a generally “T” shaped Y coil frame 158 that alsoextends the length of the coarse frame 122. The Y magnet arrays 156extend substantially parallel along the length of the bearing plates 142and are retained by the reaction assembly 20. Alternately, theconfiguration of the coil array and the magnet array can be reversed.

[0081] It should be noted that the coarse Y mover 36 is designed toallow for movement along the X axis and about the Z axis. Referring toFIG. 9, each Y magnet array 156 is sized to provide space for the Y coilframe 156 along the X axis and about the Z axis.

[0082] The desired stroke of the coarse Y mover 36 along the Y axis willvary according to the number of objects 24 retained by the fine stage14. More specifically, the stroke of the coarse Y mover along the Y axiswill need to be increased as the number of objects 24 is increased. Asuitable stroke of a single reticle 26 is between approximately 250millimeters and 350 millimeters while a suitable stroke for two reticles26 is between approximately 450 millimeters and 550 millimeters.

[0083] Importantly, the coarse Y mover 36 engages the coarse stage 18near the combination center of gravity 128. As a result of this design,the force required to move the coarse stage 18 along the X axis andabout the Z axis is minimized. This allows for the use of a smaller,lighter mass, coarse X mover 38.

[0084] In the embodiment illustrated in the Figures, the coarse X mover38 includes a pair of spaced apart voice coil actuators. In thisembodiment, the first portion 126 of the coarse X mover 38 includes apair of spaced apart coils (not shown) and the second portion 154 of thecoarse X mover 38 includes a pair of X magnet arrays 160. Each coil isdisposed within a generally “T” shaped X coil frame 162. The X magnetarrays 160 extend substantially parallel along the length of thereaction assembly 20 and are retained by the reaction assembly 20.Alternately, the configuration of the coil array and the magnet arraycan be reversed.

[0085] The reaction assembly 20 reduces and minimizes the amount ofreaction forces from the coarse movers 36, 38 that is transferredthrough the mounting frame 22 to the ground 164. The reaction assembly20 is supported above the mounting frame 22 by a fluid bearings asprovided below. Through the principle of conservation of momentum,movement of the coarse stage 18 with the coarse Y mover 36 in onedirection, moves the reaction assembly 20 in the opposite directionalong the Y axis. The reaction forces along the X axis and about the Zaxis from the coarse X mover 38 are relatively small and are transferreddirectly to the mounting plate 174 through the second portion of thecoarse X mover 154.

[0086] The design of the reaction assembly 20 can be varied to suit thedesign requirements of the stage assembly 10. In the embodimentillustrated in the Figures, the reaction assembly 20 includes the pairof spaced apart bearing plates 142, a “U” shaped bracket 166, a “L”shaped bracket 168, a bottom plate 170, a pair of end blocks 172, amounting plate 174 and a trim mover 176. The bearing plates 142, the “U”shaped bracket 166, the “L” shaped bracket 168, and the bottom plate 170each extend between and are supported by the end blocks 172. The endblocks 172 are mounted to the mounting plate 174.

[0087] As provided above, the bearing plates 142 provide a fluid bearingsurface for supporting the coarse stage 18. The “U” shaped bracket 166supports the second portion 152 of the coarse Y mover 36. Morespecifically, the “U” shaped bracket 166 supports the pair of Y magnetsarrays 156 on each side of the first portion 124 of the coarse Y mover36. The “L” shaped bracket 168 and the bottom plate 170 support the “U”shaped bracket 166 and secure the “U” shaped bracket 166 to the lowerbearing plate 142. The “L” shaped bracket 168 can include a passagewayfor directing a circulating fluid (not shown) for cooling the coarse Ymover 36.

[0088] The mounting plate 174 is generally planar shaped and includes abody section 178 and a pair of spaced apart transverse sections 180. Thesecond portion 154 of the coarse X mover 38 (i.e. the X magnet arrays160) is secured to the top of the body section 178 and each end block172 is attached to the top of each of the transverse sections 180. Themounting plate 174 also includes (i) three, spaced apart, upper Zbearing components 184, (ii) two, spaced apart, upper X bearingcomponents 186, and (iii) two, space apart, preload magnets 188.

[0089] Two of the upper Z bearing components 184 extends downward fromthe bottom of each transverse section 180 and the other upper Z bearingcomponent 184 extends downward from the bottom of the body section 178.The upper Z bearing components 184 interact with three, spaced apartlower Z bearing components 190 that are secured to the mounting frame22. More specifically, pressurized fluid is released between thecorresponding Z bearing components 184, 190 to create a fluid bearingthat maintains the reaction assembly 20 spaced apart from the mountingframe 22 along the Z axis. The fluid bearing also allows for relativemotion between the reaction assembly 20 and the mounting frame 22 sothat reaction forces from the coarse movers 36, 38 are not transferredto the mounting frame 22 and the ground 164. Alternately, the reactionassembly 20 can be supported above the mounting frame 22 by other wayssuch as magnetic type bearing (not shown).

[0090] The upper X bearing components 186 extend downward from thebottom of the body section 178. Each upper X bearing component 186 ispositioned between a pair of spaced apart lower X bearing components 192that are secured to the mounting frame 22. Pressurized fluid is releasedfrom the lower X bearing components 192 against the upper X bearingcomponent 186 to create a fluid bearing that maintains the reactionassembly 20 properly spaced relative to the mounting frame 22 along theX axis. The fluid bearing also allows for relative motion between thereaction assembly 20 and the mounting frame 22 so that reaction forcesfrom the coarse movers 36, 38 are not transferred to the mounting frame22 and the ground 164. Alternately, the reaction assembly 20 can besupported above the mounting frame 22 along the X axis by other wayssuch as magnetic type bearing (not shown).

[0091] The spaced apart preload magnets 188 extend downward from thebottom of the body section 178. The preload magnets 188 are attracted tomounting frame 22 and urge the reaction assembly 20 towards the mountingframe 22. This loads the fluid bearing created between the correspondingZ bearing components 184, 190. Alternately, for example, a vacuum couldbe created between the reaction assembly 20 and the mounting frame 22 toload the fluid bearing.

[0092] The trim mover 176 is used to make minor corrections along the Yaxis to the position of the reaction assembly 20 relative to themounting frame 22. The design of the trim mover 176 can be varied. Forexample, the trim mover 176 can be a rotary motor, a voice coil motor ora linear motor. In the embodiment illustrated in the Figures, the trimmover 176 is a rotary motor connected to both the reaction assembly 20and the mounting frame 22.

[0093] The trim mover 176 includes a body 194 and a tab 196 that ismoved by rotation of the motor. The body 194 of the trim mover 176 ismounted to one of the preload magnets 188 of the reaction assembly 20and the tab 196 is mounted to the mounting frame 22. With this design,rotation of the trim mover 176 can move the tab 196 and make minorcorrections along the Y axis to the position of the reaction assembly 20relative to the mounting frame 22. Preferably, the trim mover 176includes an encoder (not shown) that provides information regarding theposition of the reaction assembly 20 relative to the mounting frame 22along the Y axis.

[0094] Preferably, the mass ratio of the reaction assembly 20 to thecombination fine stage 14 and coarse stage 18 is high. This willminimize the movement of the reaction assembly and minimize the requiredtravel of the trim mover 176.

[0095] The mounting frame 22 is rigid and supports the reaction assembly20 above the ground 164. The design of the mounting frame 22 can bevaried to suit the design requirements of the stage assembly 10 and theexposure apparatus 28. In the embodiment illustrated in the Figures, themounting frame 22 includes a pair of side brackets 198 that aremaintained apart by a back bracket 200. One of the lower Z bearingcomponents 190 is secured to each of the side brackets 198 and the otherlower Z bearing component 190 is secured to the back bracket 200. Thetwo pairs of spaced apart lower X bearing components 192 are alsosecured to the back bracket 200.

[0096] The mounting frame 22 can be secured to the ground 164 in anumber of alternate ways. For example, as illustrated in FIG. 13, themounting frame 22 can be secured with a separate reaction frame 202 tothe ground 164. Alternately, because of the use of the reaction assembly20, the mounting frame 22 can be secured to the apparatus frame 120 withsome of the other components of the exposure apparatus 28.

[0097]FIG. 13 is a schematic view illustrating an exposure apparatus 28useful with the present invention. The exposure apparatus 28 includes anapparatus frame 120, an illumination or irradiation source 204, thereticle stage assembly 10, the lens assembly 50, and a wafer stage 206.

[0098] The exposure apparatus 28 is particularly useful as alithographic device which transfers a pattern (not shown) of anintegrated circuit from the reticle 26 onto the semiconductor wafer 30.The exposure apparatus 28 mounts to the ground 164, i.e., a floor, abase or some other supporting structure.

[0099] The apparatus frame 120 is rigid and supports the components ofthe exposure apparatus 28. The design of the apparatus frame 120 can bevaried to suit the design requirements for the rest of the exposureapparatus 28. The apparatus frame 120 illustrated in FIG. 13, supportsthe stage base 12, the wafer stage 206, the lens assembly 50, and theillumination source 204 above the ground 164. Alternately, for example,separate, individual structures (not shown) can be used to support thewafer stage 206, the illumination source 204 and the lens assembly 50above the ground 164.

[0100] The illumination source 204 emits the beam of light energy whichselectively illuminates different portions of the reticle 26 and exposesthe wafer 30. In FIG. 13, the illumination source 204 is illustrated asbeing supported above the reticle stage assembly 10. Typically, however,the illumination source 204 is secured to one of the sides of theapparatus frame 120 and the energy beam from the illumination source 204is directed to above the reticle stage assembly 10.

[0101] The lens assembly 50 projects and/or focuses the light passingthrough reticle 26 to the wafer 30. Depending upon the design of theapparatus 28, the lens assembly 50 can magnify or reduce the imageilluminated on the reticle 26.

[0102] The reticle stage assembly 10 holds and positions the reticle 26relative to the lens assembly 50 and the wafer 30. Similarly, the waferstage 206 holds and positions the wafer 30 with respect to the projectedimage of the illuminated portions of the reticle 26. In FIG. 13, thewafer stage 206 is positioned by linear motors 208. Depending upon thedesign, the apparatus 28 can also include additional motors to move thewafer stage 206. In this embodiment, the position of the wafer stage 206is monitored by an interferometer system 214. The interferometer system214 comprises a moving mirror 210 disposed on the top surface of thewafer stage 206 and a wafer interferometer 212 connected to theapparatus frame 120. The wafer interferometer 212 generates ameasurement beam 216 toward the moving mirror 210, and detects the beamreflected from the moving mirror 210. The linear motors 208 drive thewafer stage 206 based on the result of the monitoring of theinterferometer system 214.

[0103] There are a number of different types of lithographic devices.For example, the exposure apparatus 28 can be used as scanning typephotolithography system that exposes the pattern from the reticle 26onto the wafer 30, with the reticle 26 and wafer 30 movingsynchronously. In a scanning type lithographic device, the reticle 26 ismoved perpendicular to an optical axis of the lens assembly 50 by thereticle stage assembly 10 and the wafer 30 is moved perpendicular to theoptical axis of the lens assembly 50 by the wafer stage 206. Scanning ofthe reticle 26 and the wafer 30 occurs while the reticle 26 and thewafer 30 are moving synchronously.

[0104] Alternately, the exposure apparatus 28 can be a step-and-repeattype photolithography system that exposes the reticle 26 while thereticle 26 and the wafer 30 are stationary. In the step and repeatprocess, the wafer 30 is in a constant position relative to the reticle26 and the lens assembly 50 during the exposure of an individual field.Subsequently, between consecutive exposure steps, the wafer 30 isconsecutively moved by the wafer stage 206 perpendicular to the opticalaxis of the lens assembly 50 so that the next field of the wafer 30 isbrought into position relative to the lens assembly 50 and the reticle26 for exposure. Following this process, the images on the reticle 26are sequentially exposed onto the fields of the wafer 30 so that thenext field of the wafer 30 is brought into position relative to the lensassembly 50 and the reticle 26.

[0105] However, the use of the exposure apparatus 28 provided herein isnot limited to a photolithography system for semiconductormanufacturing. The exposure apparatus 28, for example, can be used as anLCD photolithography system that exposes a liquid crystal display devicepattern onto a rectangular glass plate or a photolithography system formanufacturing a thin film magnetic head. Further, the present inventioncan also be applied to a proximity photolithography system that exposesa mask pattern by closely locating a mask and a substrate without theuse of a lens assembly. Moreover, the stage assembly 10 provided hereincan be used in other devices, including other semiconductor processingequipment, machine tools, metal cutting machines, and inspectionmachines.

[0106] The illumination source 204 can be g-line (436 nm), i-line (365nm), KrF excimer laser (248 nm), ArF excimer laser (193 nm) and F₂ laser(157 nm). Alternately, the illumination source 204 can also use chargedparticle beams such as x-ray and electron beam. For instance, in thecase where an electron beam is used, thermionic emission type lanthanumhexaboride (LaB₆) or tantalum (Ta) can be used as an electron gun.Furthermore, in the case where an electron beam is used, the structurecould be such that either a mask is used or a pattern can be directlyformed on a substrate without the use of a mask.

[0107] In terms of the magnification of the lens assembly 50 included inthe photolithography system, the lens assembly 50 need not be limited toa reduction system. It could also be a lx or magnification system.

[0108] With respect to a lens assembly 50, when far ultra-violet rayssuch as the excimer laser is used, glass materials such as quartz andfluorite that transmit far ultra-violet rays is preferable to be used.When the F₂ type laser or x-ray is used, the lens assembly 50 shouldpreferably be either catadioptric or refractive (a reticle should alsopreferably be a reflective type), and when an electron beam is used,electron optics should preferably consist of electron lenses anddeflectors. The optical path for the electron beams should be in avacuum.

[0109] Also, with an exposure device that employs vacuum ultra-violetradiation (VUV) of wavelength 200 nm or lower, use of the catadioptrictype optical system can be considered. Examples of the catadioptric typeof optical system include the disclosure Japan Patent ApplicationDisclosure No.8-171054 published in the Official Gazette for Laid-OpenPatent Applications and its counterpart U.S. Pat. No. 5,668,672, as wellas Japan Patent Application Disclosure No.10-20195 and its counterpartU.S. Pat. No. 5,835,275. In these cases, the reflecting optical devicecan be a catadioptric optical system incorporating a beam splitter andconcave mirror. Japan Patent Application Disclosure No.8-334695published in the Official Gazette for Laid-Open Patent Applications andits counterpart U.S. Pat. No. 5,689,377 as well as Japan PatentApplication Disclosure No.10-3039 and its counterpart U.S. patentapplication Ser. No. 873,605 (Application Date: Jun. 12, 1997) also usea reflecting-refracting type of optical system incorporating a concavemirror, etc., but without a beam splitter, and can also be employed withthis invention. As far as is permitted, the disclosures in theabove-mentioned U.S. patents, as well as the Japan patent applicationspublished in the Official Gazette for Laid-Open Patent Applications areincorporated herein by reference.

[0110] Further, in photolithography systems, when linear motors (seeU.S. Pat. Nos. 5,623,853 or 5,528,118) are used in a wafer stage or amask (reticle) stage, the linear motors can be either an air levitationtype employing air bearings or a magnetic levitation type using Lorentzforce or reactance force. Additionally, the stage could move along aguide, or it could be a guideless type stage which uses no guide. As faras is permitted, the disclosures in U.S. Pat. Nos. 5,623,853 and5,528,118 are incorporated herein by reference.

[0111] Alternatively, one of the stages could be driven by a planarmotor, which drives the stage by electromagnetic force generated by amagnet unit having two-dimensionally arranged magnets and an armaturecoil unit having two-dimensionally arranged coils in facing positions.With this type of driving system, either one of the magnet unit or thearmature coil unit is connected to the stage and the other unit ismounted on the moving plane side of the stage.

[0112] Movement of the stages as described above generates reactionforces which can affect performance of the photolithography system.Reaction forces generated by the wafer (substrate) stage motion can bemechanically released to the floor (ground) by use of a frame member asdescribed in U.S. Pat. No. 5,528,118 and published Japanese PatentApplication Disclosure 8-166475. Additionally, reaction forces generatedby the reticle (mask) stage motion can be mechanically released to thefloor (ground) by use of a frame member as described in U.S. Pat. No.5,874,820 and published Japanese Patent Application Disclosure No.8-330224. As far as is permitted, the disclosures in U.S. Pat. Nos.5,528,118 and 5,874,820 and Japanese Patent Application Disclosure Nos.8-166475 and 8-330224 are incorporated herein by reference.

[0113] As described above, a photolithography system according to theabove described embodiments can be built by assembling varioussubsystems, including each element listed in the appended claims, insuch a manner that prescribed mechanical accuracy, electrical accuracyand optical accuracy are maintained. In order to maintain the variousaccuracies, prior to and following assembly, every optical system isadjusted to achieve its optical accuracy. Similarly, every mechanicalsystem and every electrical system are adjusted to achieve theirrespective mechanical and electrical accuracies. The process ofassembling each subsystem into a photolithography system includesmechanical interfaces, electrical circuit wiring connections and airpressure plumbing connections between each subsystem. Needless to say,there is also a process where each subsystem is assembled prior toassembling a photolithography system from the various subsystems. Once aphotolithography system is assembled using the various subsystems, totaladjustment is performed to make sure that every accuracy is maintainedin the complete photolithography system. Additionally, it is desirableto manufacture an exposure system in a clean room where the temperatureand cleanliness are controlled.

[0114] Further, semiconductor devices can be fabricated using the abovedescribed systems, by the process shown generally in FIG. 14. In step301 the device's function and performance characteristics are designed.Next, in step 302, a mask (reticle) having a pattern is designedaccording to the previous designing step, and in a parallel step 303 awafer is made from a silicon material. The mask pattern designed in step302 is exposed onto the wafer from step 303 in step 304 by aphotolithography system described hereinabove in accordance with thepresent invention. In step 305 the semiconductor device is assembled(including the dicing process, bonding process and packaging process),then finally the device is inspected in step 306.

[0115]FIG. 15 illustrates a detailed flowchart example of theabove-mentioned step 304 in the case of fabricating semiconductordevices. In FIG. 15, in step 311 (oxidation step), the wafer surface isoxidized. In step 312 (CVD step), an insulation film is formed on thewafer surface. In step 313 (electrode formation step), electrodes areformed on the wafer by vapor deposition. In step 314 (ion implantationstep), ions are implanted in the wafer. The above mentioned steps311-314 form the preprocessing steps for wafers during wafer processing,and selection is made at each step according to processing requirements.

[0116] At each stage of wafer processing, when the above-mentionedpreprocessing steps have been completed, the following post-processingsteps are implemented. During post-processing, firstly, in step 315(photoresist formation step), photoresist is applied to a wafer. Next,in step 316, (exposure step), the above-mentioned exposure device isused to transfer the circuit pattern of a mask (reticle) to a wafer.Then, in step 317 (developing step), the exposed wafer is developed, andin step 318 (etching step), parts other than residual photoresist(exposed material surface) are removed by etching. In step 319(photoresist removal step), unnecessary photoresist remaining afteretching is removed.

[0117] Multiple circuit patterns are formed by repetition of thesepreprocessing and post-processing steps.

[0118] While the particular stage assembly 10 as shown and disclosedherein is fully capable of obtaining the objects and providing theadvantages herein before stated, it is to be understood that it ismerely illustrative of the presently preferred embodiments of theinvention and that no limitations are intended to the details ofconstruction or design herein shown other than as described in theappended claims.

What is claimed is:
 1. A stage apparatus for positioning an object, thestage apparatus comprising: a first stage including a first frame and afirst supporting member that supports the first frame, the first frameholding the object and positioning the object; and a second stageincluding a second frame and a second supporting member that supportsthe second frame, the second frame being connected with the first framein a non-contact manner and positioning the first frame, and the secondsupporting member is provided independently from the first supportingmember of the first stage.
 2. The stage apparatus of claim 1 , whereinthe first stage is a fine stage that positions the object with a firstprecision, and the second stage is a coarse stage that positions thefirst frame of the first stage with a second precision that is lowerthan the first precision.
 3. The stage apparatus of claim 1 , whereinthe first stage positions the object within a first movable region andthe second stage positions the first frame of the first stage within asecond movable region that is larger than the first movable region. 4.The stage apparatus of claim 1 , further comprising a vibration damperdevice disposed between the first supporting member and the secondsupporting member.
 5. The stage apparatus of claim 4 , wherein thevibration damper device prevents a vibration, which is generated by amovement of the second stage, from propagating to the first supportmember.
 6. The stage apparatus of claim 4 , wherein the vibration damperdevice is a reaction assembly that reduces a reaction force generated bythe movement of the second stage.
 7. The stage apparatus of claim 1 ,further comprising a measurement system that measures a position of thefirst frame of the first stage, wherein the measurement system isconnected to the first supporting member.
 8. The stage apparatus ofclaim 1 , further comprising a first mover that causes a relativemovement between the first frame of the first stage and the secondstage, wherein the first mover connect the first stage and the secondstage in a non-contract manner.
 9. The stage apparatus of claim 8 ,wherein the first mover generates driving force by utilizing a magneticfield.
 10. The stage apparatus of claim 9 , wherein the first mover hasat least one electromagnet that generates the driving force.
 11. Thestage apparatus of claim 8 , further comprising a second mover thatcauses a relative movement between the second frame and the secondsupporting member along the direction substantially parallel to thedirection of driving force of the first mover, and wherein (i) a firstportion of the first mover is connected to the first frame, (ii) asecond portion of the first mover is connected to the second frame,(iii) a first portion of the second mover is connected to the secondframe, and (iv) a second portion of the second mover is connected to thesecond supporting member.
 12. The stage apparatus of claim 11 , whereinthe second mover connects the second frame and the second supportingmember in a non-contact manner.
 13. The stage apparatus of claim 12 ,wherein the second supporting member supports the second frame in anon-contact manner.
 14. The stage apparatus of claim 1 , wherein thefirst supporting member supports the first frame in a non-contactmanner.
 15. The stage apparatus of claim 14 , wherein the first stagefurther comprises a fluid bearing disposed between the first frame andthe first supporting member.
 16. An exposure apparatus for positioningan object, the exposure apparatus comprising: an illumination source;and a stage apparatus, the stage apparatus comprising: a first stageincluding a first frame and a first supporting member that supports thefirst frame, the first frame holding the object and positioning theobject; a second stage including a second frame and a second supportingmember that supports the second frame, the second frame being connectedwith the first frame of the first stage in a non-contact manner andpositioning the first frame, and the second supporting member isprovided independently from the first supporting member of the firststage.
 17. The exposure apparatus of claim 16 , further comprising anapparatus frame that holds the illumination source, wherein theapparatus frame is construed integrally with the first supporting memberof the first stage and is independent of the second supporting member ofthe second stage.
 18. The exposure apparatus of claim 16 , wherein theobject is a reticle having a pattern, and the first stage and the secondstage position the reticle.
 19. A device manufactured with the exposureapparatus according to claim 16 .
 20. A wafer on which an image has beenformed by the exposure apparatus according to claim 16 .
 21. A methodfor making a stage apparatus, the method comprising the steps of:providing a first stage including a first frame and a first supportingmember that supports the first frame, the first frame holding an objectand positioning the object; and providing a second stage including asecond frame and a second supporting member that supports the secondframe, the second frame being connected with the first frame in anon-contact manner and positioning the first frame, an the secondsupporting member is provided independently from the first supportingmember.
 22. The method of claim 21 , wherein the first stage is a finestage that positions the object with a first precision; and the secondstage is a coarse stage that positions the first frame of the firststage with a second precision that is lower than the first precision.23. The method of claim 21 , wherein the first stage positions theobject within a first movable region; and the second stage positions thefirst frame of the first stage within a second movable region that islarger than the first movable region.
 24. The method of claim 21 ,further comprising the step of disposing a vibration damper devicebetween the first supporting member and the second supporting member.25. The method of claim 24 , wherein the vibration damper deviceprevents a vibration, which is generated by a movement of the secondstage, from propagating to the first support member.
 26. The method ofclaim 24 , wherein the vibration damper device is a reactive assemblythat reduces a reaction force generated by the movement of the secondstage.
 27. The method of claim 21 , further comprising the step ofconnecting a measurement system to the first supporting member so thatthe measurement system measures a position of the first frame of thefirst stage.
 28. The method of claim 21 , further comprising the step ofcoupling a first mover to at least one of the first stage and the secondstage so that the first mover connects the first stage and the secondstage in a non-contact manner and causes a relative movement between thefirst frame of the first stage and the second stage.
 29. The method ofclaim 28 , wherein the first mover generates driving force by utilizinga magnetic field.
 30. The method of claim 29 , wherein the first moverhas at least one electromagnet that generates the driving force.
 31. Themethod of claim 28 , further comprising the step of coupling a secondmover to the second stage so that the second mover causes a relativemovement between the second frame and the second supporting member alongthe direction substantially parallel to the direction of driving forceof the first mover, wherein: (i) the step of coupling the first moverincludes the steps of connecting a first portion of the first mover tothe first frame, and connecting a second portion of the first mover tothe second frame, and (ii) the step of coupling the second moverincludes the steps of connecting a first portion of the second mover tothe second frame, and connecting a second portion of the second mover tothe second supporting member.
 32. The method of claim 31 , wherein thesecond mover connects the second frame and the second supporting memberin a non-contact manner.
 33. The method of claim 32 , wherein the secondsupporting member supports the second frame in a non-contact manner. 34.The method of claim 21 , wherein the first supporting member supportsthe first frame in a non-contact manner.
 35. The method of claim 34 ,wherein the first stage further comprises a fluid bearing disposedbetween the first frame and the first supporting member.
 36. A methodfor making an exposure apparatus including the steps of: providing anillumination source; and providing a stage apparatus, the step ofproviding the stage apparatus further comprising the steps of: providinga first stage including a first frame and a first supporting member thatsupports the first frame, the first frame holding an object andpositioning the object; and providing a second stage including a secondframe and a second supporting member that supports the second frame, thesecond frame being connected with the first frame in a non-contactmanner and positioning the first frame, and the second supporting memberis provided independently from the first supporting member.
 37. Themethod of claim 36 , further comprising the step of providing anapparatus frame that supports the illumination source, the apparatusframe being construed integrally with the first supporting member of thefirst stage and is independent of the second supporting member of thesecond stage.
 38. The method of claim 36 , wherein the object is areticle having a pattern, the first stage and the second stagepositioning the reticle.
 39. A method of making a device including atleast an exposure process, wherein the exposure process utilizes theexposure apparatus made by the method of claim 36 .
 40. A method ofmaking a wafer utilizing the exposure apparatus made by the method ofclaim 36 .